The present invention generally relates to biomedical devices, and especially ophthalmic lenses that are intended for direct placement on or in the eye such as contact lenses or intraocular lenses, where the devices and lenses are made of a poly(2-oxazoline) homopolymer or copolymer.
Hydrogels represent a desirable class of materials for many biomedical device applications, including contact lenses and intraocular lenses. Hydrogels are hydrated, cross-linked polymeric systems that contain water in an equilibrium state. Typically, a monomeric mixture including at least one hydrophilic monomer is polymerized by free radical polymerization. One of the hydrophilic monomers may function as a crosslinking agent (a crosslinker being defined as a monomer having multiple polymerizable functionalities) or a separate crosslinking comonomer may be employed. One class of hydrogels are silicone hydrogels, which are characterized by the inclusion of a silicone-containing material in the monomeric mixture.
U.S. Pat. Nos. 5,352,714 (Lai et al.) and 5,357,013 (Bambury et al.) disclose certain 2-oxazolin-5-one monomers having 2-vinyl substitution that are useful as wetting agents in ophthalmic lens polymeric materials, including silicone hydrogel materials. A representative 2-oxazolin-5-one compound disclosed in these patents is 2-vinyl-4,4-dimethyl-2-oxazolin-5-one (VDMO).
The present invention provides a novel biomedical devices based on the subject materials. These materials are biocompatible and may be manufactured (for example, molded or machined) into a desired shape, and exhibit suitable physical properties for prolonged contact with the body. The materials are also optically clear and suitable for ophthalmic lens applications.
This invention provides a biomedical device formed from the polymerization product of a monomeric mixture comprising a poly(2-oxazoline) endcapped with an ethylenically unsaturated radical. Preferred devices are ophthalmic lenses intended for direct contact with the eye, especially contact lenses and intraocular lenses.
A first preferred class of poly(2-oxazoline) materials is based on macromonomers of the formula: 
where R is a polymerizable, ethylenically unsaturated radical;
Rxe2x80x2 is selected from the group consisting of alkyl, haloalkyl, alkene, alkyne, cycloalkyl, halocycloalkyl, aryl, haloaryl, aralkyl and haloaralkyl; and
n is at least 2.
A second preferred class of poly(2-oxazoline) materials is based on telechelics of the formula: 
where each R is independently a polymerizable, ethylenically unsaturated radical;
each Rxe2x80x2 is independently selected from the group consisting of alkyl, haloalkyl, alkene, alkyne, cycloalkyl, halocycloalkyl, aryl, haloaryl, aralkyl and haloaralkyl;
Z is a divalent linkage; and
each of x and y is at least 1.